Over the back return

[Viv]

If I plumb over the back of the tank return from the sump, is there a certain way the drains from the overflow should go to the sump? ie. should both bulkheads from the left go together, both on the right go together, or should it be a combination of one from left and one from right joined together. The bulkheads in my overflow are of different sizes. Does it matter?

[Geoff]

it does not matter. you are thinking to much.

i actually think it is better to have them seperate that way they can find their own equilibrium without fighting the other. if you do need to combine them, than make the combined tube significantly bigger than the non combined pipes. doubling the size is good. that more than doubles the internal volume.

G~